Conventionally, such a method for deriving an equivalent circuit model of a capacitor is used in a circuit simulation for designing an electronic circuit. Circuit simulators, such as SPICE (Simulation Program with Integrated Circuit Emphasis), are used for circuit simulations, and some circuit simulators are available for use on websites of electronic component manufacturers. Users access the websites of the electronic component manufacturers from terminals, such as a personal computer, through the Internet and use the circuit simulators.
Disclosed in Japanese Unexamined Patent Application Publication No. 2002-259482, for example, is an existing method for deriving an equivalent circuit model of a capacitor. According to this method for deriving an equivalent circuit model, given frequency characteristics of a capacitor are input in a first step, and, in a second step, one of an RC circuit, an RL circuit, and an RCL circuit is formed as an equivalent circuit model, or a circuit that can be simulated in a time domain, by using a resistance (R), a capacitance (C), and an inductance (L) that are not dependent on the frequency. Then, in a third step, an evaluation function is composed for determining the accuracy of the equivalent circuit model formed in the second step, and, in a fourth step, the evaluation function composed in the third step is minimized so as to determine a circuit constant.
According to Japanese Unexamined Patent Application Publication No. 2002-259482, through the configuration described above, such an equivalent circuit model of a capacitor, of which an impedance is indicated in a frequency domain, that can be simulated in a time domain is derived, and the electrical characteristics of the capacitor in the frequency domain or in the time domain are predicted through a circuit simulation.